Alongside Dirk Brzezinski and Peter Carl,[1] Hess hacked into networks of military and industrial computers based in the United States, Europe and East Asia, and sold the information to the Soviet KGB for US$54,000.
[1][4] Hess's hacking activities were discovered in 1986 by Clifford Stoll, an astronomer turned system administrator of the computer center of the Lawrence Berkeley Laboratory (LBL) in California.
[1] The facilities that Hess breached included:[1][11] Stoll, with the help of local authorities, traced the call to a Tymnet switch in Oakland, California.
Tymnet officials helped LBL trace the various calls, even though the hacker attempted to conceal their origin.
Enlisting the aid of AT&T and the Federal Bureau of Investigation (FBI), Stoll eventually determined that the calls were being "piggybacked" across the United States, but originated from the West German city of Hanover.
[12] Stoll trapped Hess by creating records of a bogus military project conducted on LBL computers; according to The Cuckoo's Egg, he and his girlfriend conceived this plan while showering, giving it the unofficial name of "Operation Showerhead".
[13] At the time, this type of hacking was unheard of, and it was a considerable challenge to get the cooperation of the FBI and the West German government.